The patent document DE 3638739 A1 relates to a thermal adjusting drive comprising a pressure chamber with an adjusting piston and containing a medium expanding when heated, together with a heat source. Foam-forming liquid is contained in the chamber, pressure being generated by a gas soluble in it.
Silicone oil mixed with a wetting agent can be used as the liquid, and pressure can be generated by a founded hydrocarbon, while the heat source can be electric.
The patent document DE 102005039270 A1 relates to a device to transform heat energy into mechanical energy. Expanded through applied heat, expanding bodies are interconnected as desired in a cascade or in parallel. Lengthening produced through heat and shortening produced by cooling is made useable at the end of the expanding bodies in the form of energy. Linked to the expanding bodies output, a cylinder piston system reduces overall strokes. A mixing/heat exchanger device optimizes the use of heat.
The patent document DE 3526289 A1 relates to mechanical power production, e. g. to drive a pump by alternately heating and cooling e. g. oil in pressure vessel containing thin tube bundle heated and cooled to drive piston.
The patent document U.S. Pat. No. 4,079,596 relates to heat engines and heat pumps. FIGS. 6-a and 6-b respectively illustrates a longitudinal cross-section and a transverse cross-section of a stationary type new heat engine. It comprises a multivoid metal block and heaters with manifold means at each end. The multivoid contains a first set of conduits and a second set of conduits. The first set of conduits is used to contain an S/L type working medium and a heating medium, intermediate heat exchange mediums and a cooling medium are to pass through the second set of conduits to cause the working medium to undergo the four steps, viz. A-B, B-C, CD and D-A, described.
A main disadvantage with the above described solutions is that the power density (output power per system weight and/or volume) and the manufacturing cost are not optimized.